Method and device for the production of a packaged unit

ABSTRACT

The invention relates to a method and a device for producing a packaged unit. Individual products ( 3 ) are combined into a product cluster ( 2 ) and are fixed relative to each other by means of a shrink film ( 1 ). For this purpose, the shrink film ( 1 ) is wrapped around the product cluster ( 2 ) such that at least one lateral opening ( 5 ) is formed, and the shrink film ( 1 ) is then shrunk. According to the invention, the shrink film ( 1 ) is placed against the product cluster ( 2 ) at least in the region of the lateral opening ( 5 ) such that a closed surface is formed in the shape of a closure ( 6 ) that has optionally overlapping folded zones ( 8   a,    8   b ).

The invention relates to a method and a device for producing a packaged unit, according to which method and device individual products are combined to form a product cluster and are secured against each other by means of a shrinkable covering or packaging. In the case of these types of shrinkable packaging, so-called shrink eyes are usually produced on the lateral surfaces where the shrink film does not form a closed surface but as a rule leaves at least one opening open and this has a negative effect on the stability of such shrink packaging to a not inconsiderable extent.

A method and an associated device for forming shrink packaging have been made known in DE 10 2006 036 590 A1. In this case, to form a group, the shrink film is wrapped around a group unit such that each group is surrounded at the top and at the bottom. On two oppositely situated sides the shrink film does not abut against the group but rather protrudes from said group and consequently forms openings, through which hot air passes into the group during the subsequent shrinking process. The size of the shrink film is reduced through the effect of hot air and/or heat on the shrink film.

In this case the result of the reduction in the size of the shrink film is that said shrink film abuts tightly against the product group and is consequently secured. The so-called shrink eyes simply remain as openings on the lateral faces, said shrink eyes in the case of the finished packaged unit still not protecting the individual products totally against unauthorized access and over and above this also having a negative effect of the stability of the packaging.

For this reason many packers act to reinforce the packaged units to be produced by additionally inserting stability means. In the simplest case here this could be cardboard bottoms or so-called pads or trays onto which the products are deposited and form the product cluster. Once the packaged unit assembled in this manner has been wrapped around with the shrink film, the necessary stability is achieved.

However, the depositing of the products onto the aforementioned cardboard base requires an additional processing step. To this is added that the cardboard base has to be disposed of, for example by the consumer or in a shop and naturally this is linked to not inconsiderable costs when producing the packaged unit.—This is where the invention aims to provide a remedy.

The technical problem underlying the invention is to develop further a method and a device of the afore-described embodiment such that the costs are reduced with at the same time unchanged functionality.

This problem is solved in that in the case of a generic method it is provided that the shrink film is placed against the product cluster at least in the region of the lateral faces, or of the former shrink eye, thereby forming a closure surface in the form of a closure with, where applicable, overlapping fold regions.

According to the invention, first of all the shrink packaging or the cut of the shrink film is dimensioned such that in each case it forms lateral protrusions beyond the product cluster, said protrusions then being placed against the product clusters in the region of associated lateral faces. This means that the lateral protrusions are capable of generating a closed surface of the shrink film at the lateral faces of the product cluster, such that the lateral faces that were formerly at least partially open experience a closure, that-is-to-say are provided with a shrink eye closure.

The lateral protrusions of the shrink film, therefore, are placed against the surface of the product cluster at least on the region of the former shrink eye and here form the already mentioned closed surface, which provides a closure. In this case it is understood that in the majority of applications the shrink film is actively placed against the product cluster at least in the region of the lateral faces; this means that the shrink film can also be placed in other regions of the product cluster if this is necessary.

For example, it is conceivable within the framework of the invention that the placing of the shrink film against the product cluster can be carried out in a contactless manner, that is to say without using additional manipulation units. In this case, it has proved of value for the shrink film to be electrostatically charged. Such electrostatic charging is not difficult because the shrink film is advantageously a plastics material shrink film, for example made from PE (polyethylene). These types of plastic material films can be easily charged electrostatically, such as is described in an exemplary and non-restricting manner, for example, in DE 10 2005 024 380 A1 or also DE 101 44 287 A1, to which express reference is made.

At any rate, the previously electrostatically charged shrink film can easily be applied in a contactless manner, without the use of additional manipulation units, to the lateral faces of the product cluster in the region of the former shrink eyes and ensures the desired securing of the shrink film in this region.

As an alternative to the described contactless securing of the lateral protrusions to the lateral faces in the region of the respective opening, it is alternatively or additionally also possible to carry out the placing by means of one or a plurality of manipulation units—by means of contact. Said one or plurality of manipulation units are usually known guiding means, guide rods, run-up elements or even one or a plurality of brushes. By way of said manipulation units, for example the one or the plurality of brushes, the lateral protrusions of the shrink film can be placed against the product cluster, with where applicable overlapping fold regions.

The visual appearance of the shrink packaging can be improved in some applications when measures are taken to prevent, in a reliable manner, the finished positioned shrink films pushing or sliding together or also pushing or sliding in relation to the product cluster.

First of all it is possible to select the electrostatic charging such that the obtainable adhesive strength between the overlapping shrink film or also between the shrink film and the associated product cluster or the respective surrounding area prevent, in a reliably manner, the shrink film being displaced in an undesired manner.

Another possibility for securing the shrink film is to bond together the overlapping regions and/or the overlapping fold regions of the shrink film. To this end, the shrink film can be provided with an adhesive coating, which is advantageously applied in the region of the lateral protrusions from the start or is applied once the product cluster has been wrapped around.

In addition, it is also possible to bond the shrink film by means of a method where adhesive is applied onto the shrink film by means of an injecting or spraying operation.

In principle, the fold regions can naturally also be fused by the shrinking operation itself, as has long been known from the application of shrink films.

In order to be able to provide a closed surface as perfectly as possible, it has proved of worth in certain applications when the shrink film is secured against the product cluster at least in the region of the lateral faces of the product cluster. This means that the lateral protrusions in the region of the lateral faces are not only actively placed against the product cluster but are additionally secured to the product cluster. Different types of securement can be used for this purpose.

As soon as the lateral protrusions are moved towards the lateral faces to be closed, the overlapping fold regions are formed and the adhesive present in the overlapping region or introduced or the fusing ensures that the individual folds can no longer be separated from each other.

In each case, the subsequent shrinking operation, for example in a shrink tunnel, through the effect of hot air, heat radiation, etc., provides that any creases or even waves in the shrink film are no longer important because the shrink film contracts during this operation and fixedly surrounds the product cluster and, as a result, the products that are in the form of a group. Because in the case of this operation according to the invention, the holes or openings that formerly were usual on the lateral faces of the product cluster are not created, the product cluster is encased by totally and completely closed film packaging. This means that the stability of a packaged unit produced in this manner is clearly greater than in previous embodiments. In reality, the degree of stability that can be obtained corresponds to those packaged units with shrink eyes and additional cardboard, but without such additional reinforcing measures.

This means that, within the framework of the invention, reinforcing cardboard bottoms, introduced cardboard strips, etc., are totally unnecessary in many applications, in other applications the dimensions, for example the thickness, of the cardboard bottom or cardboard strips can be reduced such that a cost saving is produced here too.

Finally, the packaged unit according to the invention, essentially comprising the product cluster and the surrounding shrink film encasing it, without any additional reinforcement already has very great stability for the storage process and/or the connecting transport of the products. Any manipulation of the products when the products are presented for example in the shop is almost completely prevented compared to previous embodiments. These are the essential advantages.

According to an advantageous development, the shrink film is wrapped around the product cluster with overlapping edges and is subsequently shrunk on. In the majority of cases the overlapping regions are the longitudinal edges because the shrink film is wrapped around the product cluster in its longitudinal direction, such that the aforementioned openings or shrink eyes remain in the transverse direction of the product cluster after this operation and at respective associated lateral faces and are closed according to the invention.

In order to realize the closure of the lateral openings or shrink eyes in detail, it has proved of worth when they are made up by two narrow side folds and two broad side folds, which, in each case, result from the lateral protrusions of the shrink film beyond the lateral faces. The two narrow side folds are produced in that the lateral protrusions of the shrink film wrapped around the product cluster on the narrow sides of the product cluster are placed against said narrow sides. The broad side folds are produced on account of the fact that the lateral protrusions on the wide sides of the product cluster are subject to the described placing operation. In the majority of cases the placing of the associated narrow side protrusions and wide side protrusions is effected in that suitable manipulation units place the respective protrusions against the associated side face of the product cluster. Working with elements such as guiding means, guide rods or also run-on elements has proved valuable in this case.

Working with brushes in each case has also proved valuable, preferably with rotating brushes that are connected, for example, to pivot arms, are moved by way of said pivot arms and accomplish the described folding operation.

As a rule, the broad side protrusions and the narrow side protrusions or the associated wide side folds are secured together to the narrow side folds. To this end, associated and overlapping fold regions may be bonded together or experience mutual securement by the time the shrink film has been shrunk on. This means that the described bonding is actually an unnecessary option.

In order to obtain this in detail, the narrow side folds are produced initially followed by the broad side folds. For this purpose, therefore, the narrow side protrusions are initially placed against the corresponding lateral face by means of the associated manipulation units or brushes, followed finally by the wide side protrusions or associated wide side folds. In this case it has proved altogether favourable when the product cluster is initially wrapped loosely into the cling film, the shrink film overlapping advantageously at its edges, in the majority of cases the longitudinal edges. In this way during the subsequent shrinking on it is ensured that the shrink film does not expose any region of the product cluster and the product cluster is encased over its entire surface in a closed manner.

The invention is explained below by way of one drawing representing just one exemplary embodiment, in which, in detail:

FIG. 1 shows an overview of a device according to the invention for producing a packaged unit,

FIG. 2 shows a front view of the object in FIG. 1 from direction X and

FIG. 3 shows the packaged unit produced as a whole.

The Figures show a device for producing a packaged unit. The packaged unit, as evidenced by FIGS. 1-3, essentially comprises a shrink film 1 and a product cluster 2 that is encased by the shrink film 1. The product cluster 2, in its turn, is formed from individual products 3, which can be seen the best in FIG. 3. In the exemplary embodiment, the products 3 are cans, more precisely beverage cans, that-is-to-say in the majority of cases rotationally symmetrical and in particular cylindrical containers, preferably for accommodating beverages. In principle, conventional cans for accommodating foodstuffs can also be combined as products 3 to form a packaged unit in the manner described below.

To this end, the products 3 are initially locked out of a product stream by means of a separating device (not shown) and are combined to form the product cluster 2; they are then aligned and compacted to the extent where they abut against each other. The shrink film 1 is then used to secure the products 3 or the product cluster 2 so that packaged units that have been produced in this manner can be better stored and/or conveyed.

To this end, the shrink film 1 is initially loosely wrapped around the product cluster 2, as is shown in FIG. 2. This may by effected by means of a winding machine (not expressly shown). In the case of this operation, the shrink film 1 is wrapped around the product cluster 2 such that respective edges 1 a, 1 b overlap, as can be seen in FIG. 1. In the exemplary embodiment but not in a restricting manner, the edges 1 a, 1 b are longitudinal edges 1 a, 1 b of the shrink film 1.

In reality, the shrink film 1 is wrapped around the product cluster 2 in the longitudinal direction L, but this is obviously not mandatory. It can be seen that the packaged unit formed in this manner has lateral protrusions 4 a, 4 b in comparison with an associated lateral face 2 a of the product cluster. In this case, the lateral protrusions 4 a, 4 b of the shrink film 1 are dimensioned overall such that the shrink film 1 closes the respective lateral face 2 a when the lateral protrusions 4 a, 4 b are placed against the lateral face 2 a or the product cluster 2.

In reality, the shrink film 1, initially wrapped in a hose-shaped manner around the product cluster 2 corresponding to the representation in FIG. 1, in each case forms an opening 5 in the region of the two lateral faces 2 a. Said opening 5 has only one closure 6, which is represented in FIG. 2.

The closure 6 is defined in that the shrink film 1 or its lateral protrusions 4 a, 4 b are placed against the product cluster 2 in the region of the opening 5 thereby forming a closed surface. For this purpose, along with the aformentioned separating device and a shrinking device placed at the end of the production path for the final mutual securing of the products 3 by way of the shrink film 1, the device also has a plurality of manipulation elements 7, which are indicated in FIG. 2, for producing the packaged unit represented.

The respective manipulation unit 7 is provided, for example, with at least one brush 7 a, which is supported by a pivot arm 7 b. The brush 7 a rotates about an axis defined by the pivot arm 7 b but this is not mandatory. By way of the brush 7 a or all the manipulation units 7, the respective lateral protrusions 4 a, 4 b of the shrink film 1 are placed against the product cluster 2 in the region of the opening 5. At the same time overlapping fold regions 8 a, 8 b are formed and can also be seen in FIG. 2. A total of four brushes 7 a are realized, in each case one brush 7 a per lateral face of the product cluster 2, which in the majority of cases is block-shaped.

The lateral protrusions 4 a, 4 b, on the one hand, are narrow side protrusions 4 a and, on the other hand, are broad side protrusions 4 b. The broad side protrusions 4 b are placed against the lateral faces 2 a by means of the associated manipulation units 7 on the corresponding broad sides of the block-shaped product cluster 2. The fold regions 8 b according to FIG. 2 in the exemplary embodiment are formed in this way. Said fold regions 8 b corresponding to FIG. 2 may be secured or become secured to the lateral face 2 a by the shrink film 1 having been completely charged electrostatically beforehand and the manipulation units 7 being responsible for moving the associated lateral protrusions nearer until they are attracted by the electrostatically charged lateral face 2 a. As an alternative or in addition to this, it is also possible for the fold regions 8 b to be bonded together (or to the product cluster 2). The same is also true for the narrow protrusions 4 a and the resultant fold regions 8 a.

In each case, the placing of the narrow side protrusions 4 a is carried out first such that initially the two associated narrow side folds 8 a are placed against the lateral face 2 a to be covered. The two broad side protrusions 4 b are then placed against the lateral face 2 a and here form the broad side folds 8 b. In the case of this operation, generally speaking the broad side folds 8 b are connected to the narrow side folds 8 a. This can be effected by means of the afore-described electrostatic charging of the shrink film 1 in its entirety or at least of the lateral protrusions 4 a, 4 b and/or by means of bonding the fold regions 8 a, 8 b.

After said described operations, the packaged unit corresponding to FIG. 2 is moved into a shrink tunnel or a comparable shrinking device, in which the shrink film 1 is shrunk onto the product cluster 2. At the same time, the products experience mutual securement because the size of the shrink film 1 is reduced during this operation. By the lateral faces that were formerly open due to the shrink eyes being covered by a closed surface through the method of operation according to the invention and being closed through the interaction of the narrow side folds 8 a and broad side folds 8 b, the shrink film 1 encases the product cluster 2 completely even after the shrinking-on operation. As a result there is no express need to attach additional stabilizing elements such as, for example, cardboard covers, etc. This reduces the production costs and the expenditure.

As already represented, in the case of many other applications where additional stabilizing elements cannot be dispensed with entirely, the dimensions of the stabilizing elements can be reduced, for example the material thickness can be reduced, thereby producing a cost saving even in such applications.

The afore-described electrostatic charging of the shrink film 1 including at least the lateral protrusions 4 a, 4 b can be performed before, during or after the described folding operation. This means that the narrow side folds 8 a and broad side folds 8 b can then be electrostatically charged after their production as in FIG. 2 in order to prevent them coming unfolded again. In each case, the shrink film 1 remains in its position after the described operations (also and in particular in the region of the closure 6) and is also not displaced by a possible hot air fan in the interior of the shrink tunnel. This means that it is possible for the shrink film 1 to surround the product cluster without any gaps and, in particular, also to obtain a reliable closure 6 for the lateral faces that were formerly open. These are the essential advantages of the invention. 

1. A method for producing a packaged unit from individual products combined to form one product cluster, said method comprising: wrapping shrink film around the product cluster thereby forming at least one lateral opening, placing the shrink film against the product cluster at least in the region of the lateral opening thereby forming a closed surface in the shape of a closure with, where applicable, overlapping fold regions, and shrinking the shrink film, thereby securing said individual products against each other.
 2. The method of claim 1, further comprising securing the shrink film on the product cluster at least in the region of the closure.
 3. The method of claim 2, wherein securing the shrink film comprises securing the shrink film in a contactless manner.
 4. The method of claim 1, wherein wrapping the shrink film comprises wrapping the shrink film around the product cluster in a way that results in overlapping edges.
 5. An apparatus for producing a packaged unit, said apparatus comprising: a separating device, which separates out individual products from a product stream and combines them to form a product cluster, a shrinking device for securing the product cluster on all sides by applying a shrink film, wherein the shrink film is wrapped around the product cluster thereby forming at least one lateral opening before being shrunk on, and a manipulation unit, which places the shrink film against the product cluster at least in the region of the lateral opening thereby forming a closed surface in the form of a closure with, where applicable, overlapping fold regions.
 6. The apparatus of claim 5, wherein the manipulation unit comprises a bonding device for placing the film in position in a contactless manner.
 7. The apparatus of claim 5, wherein the manipulation unit comprises at least one brush adapted to place laterally protruding ends of the shrink film against the product cluster in the region of the lateral opening with, where applicable, overlapping fold regions.
 8. The apparatus of claim 7, further comprising three additional brushes, thereby providing a total of four brushes, each of which is assigned to operate on a corresponding lateral face of the product cluster.
 9. The apparatus of claim 7, further comprising a pivoting arm for rotating and moving the brush.
 10. A packaged unit comprising: individual products assembled and combined to form one product cluster, shrink film securing said individual products relative to each other, the shrink film being wrapped around the product cluster thereby forming at least one lateral opening and being shrunk on, and a closure produced when the shrink film is placed against the product cluster at least in the region of the lateral openings thereby forming a closed surface with, where applicable, overlapping fold regions.
 11. The packaged unit of claim 10, wherein, the closure comprises two narrow side folds and two broad side folds that cover the two narrow side folds to form overlapping fold regions.
 12. The packaged unit of claim 11, wherein the broad side folds are secured together to the narrow side folds.
 13. The packaged unit of claim 11, wherein the overlapping fold regions are bonded together.
 14. The packaged unit of claim 11, wherein the narrow side folds are produced initially, followed by the broad side folds.
 15. The packaged unit of claim 10, wherein the shrink film wrapped around the product cluster overlaps at its edges.
 16. The method of claim 3, wherein securing the shrink film comprises securing the shrink film electrostatically.
 17. The method of claim 3, wherein securing the shrink film comprises securing the shrink film by bonding overlapping fold regions.
 18. The method of claim 3, wherein securing the shrink film comprises using a manipulating unit to secure the shrink film.
 19. The apparatus of claim 5, wherein the manipulation unit comprises an electrostatic charging unit for placing the shrink film in position in a contactless manner. 